660 replies to this topic

[matejmihelcic]

Hi,

 

Here is my first DSO images captured with beta ASI1600MM-Cool. I control camera through Voyager in MaximDL (ASCOM driver) on Win 7 and Win 10. Connection to PC was used USB 2.0 and USB3.0.

First light: Image with M105 and few surrounding galaxies were captured with small 60-mm f5,5 (work on f4,3) APO. Image consists L:8x300, RGB:5x300/channel. There are no dark, bias and flats used. Camera was cooled  on -30°C without any problems. Image FOV 234x177 arcmin (3.01 arcsec/px).

 

Other test images were captured with my AS300 astrograph.

M5: -30°C, RGB 8 x 60 sec/channel. There are no dark, bias and flats used.
M100: -30°C, L 1 x 300 sec. There are no dark, bias and flats used.
BIAS KAF8300 vs. ASI1600: 1:1

DARK KAF8300 vs. ASI1600: 1:1, -30°C, dark 300 sec

M100 KAF8300 vs. ASI1600: 1:2, L filter, 300 sec. Images were captured with the same telescope but not at same night. KAF8300 image was captured without moon presence, ASI 1600 image was captured under 6 days old moon and under poorer conditions as were at image with KAF8300. There are no dark, bias and flats used.


 

All images are available on DB link: https://www.dropbox....xY2O43QRSa?dl=0
 

Few words about filters. I used ASI1600MM-Cool with XAGIL 8x1,25" FW and mounted filters. Distance CMOS - filters glass was around 20 mm.

 

Camera interface
I used values 0/10 (highest dynamic range) which is recommended for long exposures


 

NOTICE: All images were captured under poor conditions; bad seeing, clouds, strong ground wind and presence of moon! I hope for more stable weather in next days for DSO imaging with  ASI1600MM-Cool.

 

Kind regards,

Matej Mihelčič

Edited by matejmihelcic, 18 April 2016 - 05:23 PM.

[Becomart]

This looks promising! 

[FiremanDan]

I am looking into a new camera since I got my mount problem solved WAY under budget. Coming from a DSLR I am sure this would be an improvement, but I am still torn between this and an 8300 CCD chip and/or holding out for a larger sensor cooled mono CMOS that I am sure is around the corner. 

[entilza]

Nice thanks for the report. Could you take a dark for us to take a look at? Thanks!

[matejmihelcic]

DB link was updated with DARK_ASI1600

[schmeah]

The images look great! But the dark does show that there is a fair amount of amp glow. I'm surprised you did not have to subtract that out.

 

Derek

[entilza]

Hey thanks for the Dark.  I think it actually looks great, Derek do you think that's a fair amount?  It looks great to me.  It actually looks better than the example dark provided by ASI.  Also the read noise is less.

 

Read noise from this Matej's camera:  1.86

Read noise from ZWO sample:  2.07

 

 

Edit:  I redid the sample screenshot to show the dark amp glow as best as I could figure out.

Edited by entilza, 17 April 2016 - 06:40 PM.

[Jon Rista]

Personally, I would want to eliminate that amp glow, but everyone has different tolerances.

 

As for the read noise, isn't the 1600 a variable gain camera? I believe the read noise would depend on the gain setting, and from what I read on the ZWO site, it can get under 1.5e-. 

[schmeah]

Hey thanks for the Dark.  I think it actually looks great, Derek do you think that's a fair amount?  It looks great to me.  It actually looks better than the example dark provided by ASI.  Also the read noise is less.

 

Read noise from this Matej's camera:  1.86

Read noise from ZWO sample:  2.07

 

 

 

Edit:  I redid the sample screenshot to show the dark amp glow as best as I could figure out.

 

The amp glow is less apparent on your screen shot then when I open it with my calibration software.  When I said 'fair amount", perhaps I should have said "some". I have no idea how much is a "fair amount" nor how much is too much. The images look really good, and as I have said before, this seems like a great low cost alternative for short FL / wide field imaging.

 

Derek

[andysea]

I wonder why the ADC is only 12 bit. It seems that it would seriously limit the dynamic range, unless I am missing something.

[akulapanam]

I wonder why the ADC is only 12 bit. It seems that it would seriously limit the dynamic range, unless I am missing something.

Most if not all CMOS cameras going forward will be 12 bit and 14 bit max just like DSLRs today. Stacking will restore the dynamic range.

[Midnight Dan]

 The images look really good, and as I have said before, this seems like a great low cost alternative for short FL / wide field imaging.

 

Why would you limit this to short FL imaging?

 

-Dan

[Phil Hosey]

 

 The images look really good, and as I have said before, this seems like a great low cost alternative for short FL / wide field imaging.

 

Why would you limit this to short FL imaging?

 

-Dan

 

Probably because the pixel size is so small.  You would quickly get over-sampled with longer focal lengths.

[Midnight Dan]

 

 

 The images look really good, and as I have said before, this seems like a great low cost alternative for short FL / wide field imaging.

 

Why would you limit this to short FL imaging?

 

-Dan

 

Probably because the pixel size is so small.  You would quickly get over-sampled with longer focal lengths.

 

 

 

Doesn't really seem like that would limit it to wide field.  You generally want to oversample at 2x.  An 8"SCT at 2032mm would have a Dawe's limit of 0.57", and this camera would produce an image scale of 0.39"/pixel.  So it's not a little less than 2x oversampled.  

 

Of course, seeing might not let you get to that resolution, but good skies at a high location like Arizona might give you 1.0" seeing or less, which means this camera would be about 2.5x oversampled.  Where I live, we're more likely to see 2" to 4" seeing, but you can always bin the output if you want.

 

And the numbers above are the fairly extreme case of imaging at native focal length with an 8" SCT.  A more realistic case is using an SCT with a focal reducer, which just makes the sampling ratio more favorable.

 

Fact is, many people these days image with DSLRs which have pixels in a similar size range.  I do so all the time and it definitely doesn't limit me to wide field images.

 

-Dan

[bigeastro]

I suppose this can bin 2x2 which could help in better matching longer focal length scopes? It does seem like a good match for shorter focal length scopes.

[jlandy]

ive been looking for a replacement for the t3i... have been torn between the 174mm and the 1600mm... this post might be the kicker for me. A QE graph would definitely sway me one way or the other

[andysea]

 

I wonder why the ADC is only 12 bit. It seems that it would seriously limit the dynamic range, unless I am missing something.

Most if not all CMOS cameras going forward will be 12 bit and 14 bit max just like DSLRs today. Stacking will restore the dynamic range.

 

What is the correlation between CMOS and 12 or 14 bit ADC versus 16bit?

[Thirteen]

ive been looking for a replacement for the t3i... have been torn between the 174mm and the 1600mm... this post might be the kicker for me. A QE graph would definitely sway me one way or the other

 

According to ZWO, QE is not published by the manufacturer and they claim in-house testing would be difficult.   I'm not sure we will see an absolute QE curver for this chip, unfortunately.   ZWO estimated it to be around 60% for the mono, but there wasn't an explaination on how they arrived at that.

 

Ultimately, I think the decision between the 174 and 1600 should be made on the following considerations:

(1) which is the best fit for image scale (with binning options), then

(2) is the FOV of the 174 too restrictive for your purposes, then

(3) is the supposed QE increase of 15-20% on the 174 important to you. 

[A. Viegas]

 

ive been looking for a replacement for the t3i... have been torn between the 174mm and the 1600mm... this post might be the kicker for me. A QE graph would definitely sway me one way or the other

 

According to ZWO, QE is not published by the manufacturer and they claim in-house testing would be difficult.   I'm not sure we will see an absolute QE curver for this chip, unfortunately.   ZWO estimated it to be around 60% for the mono, but there wasn't an explaination on how they arrived at that.

 

Ultimately, I think the decision between the 174 and 1600 should be made on the following considerations:

(1) which is the best fit for image scale (with binning options), then

(2) is the FOV of the 174 too restrictive for your purposes, then

(3) is the supposed QE increase of 15-20% on the 174 important to you. 

 

 

Also consider the rather small cost increase of the 1600MM to the 174MM, about $280 difference for the cooled versions.   That seems like a small price to pay for the much larger sensor, which if you bin at 2x2 is still over twice the pixels of the 174MM.    Of course it depends on your equipment and the type of imaging you are planning to do, with the 174MM perhaps a better choice if you are thinking about also doing planetary work, otherwise given the very small price increase, it seems to me the 1600MM is at a very compelling price point.

Al

[jlandy]

 

ive been looking for a replacement for the t3i... have been torn between the 174mm and the 1600mm... this post might be the kicker for me. A QE graph would definitely sway me one way or the other

 

According to ZWO, QE is not published by the manufacturer and they claim in-house testing would be difficult.   I'm not sure we will see an absolute QE curver for this chip, unfortunately.   ZWO estimated it to be around 60% for the mono, but there wasn't an explaination on how they arrived at that.

 

Ultimately, I think the decision between the 174 and 1600 should be made on the following considerations:

(1) which is the best fit for image scale (with binning options), then

(2) is the FOV of the 174 too restrictive for your purposes, then

(3) is the supposed QE increase of 15-20% on the 174 important to you. 

 

 

I was out debugging the new computer doing some tests on Jupiter, what hit me was how hard it was to find the thing with such a small chip (using the asi120mm) - it hit me that I might get very frustrated with the 174 if I was struggling to find my target. Your pictures with the 174 are really in the inspiration for me to consider that option, but I'm starting to thing the 1600 might be a better fit for me starting out with mono imaging

[Thirteen]

 

 

ive been looking for a replacement for the t3i... have been torn between the 174mm and the 1600mm... this post might be the kicker for me. A QE graph would definitely sway me one way or the other

 

According to ZWO, QE is not published by the manufacturer and they claim in-house testing would be difficult.   I'm not sure we will see an absolute QE curver for this chip, unfortunately.   ZWO estimated it to be around 60% for the mono, but there wasn't an explaination on how they arrived at that.

 

Ultimately, I think the decision between the 174 and 1600 should be made on the following considerations:

(1) which is the best fit for image scale (with binning options), then

(2) is the FOV of the 174 too restrictive for your purposes, then

(3) is the supposed QE increase of 15-20% on the 174 important to you. 

 

 

Also consider the rather small cost increase of the 1600MM to the 174MM, about $280 difference for the cooled versions.   That seems like a small price to pay for the much larger sensor, which if you bin at 2x2 is still over twice the pixels of the 174MM.    Of course it depends on your equipment and the type of imaging you are planning to do, with the 174MM perhaps a better choice if you are thinking about also doing planetary work, otherwise given the very small price increase, it seems to me the 1600MM is at a very compelling price point.

Al

 

 

I totally agree with this.  My point is that you just have to consider what works for you.  I did leave out the part about planetary which is very much in favor of the 174.     

 

Ultimately, as a 174 owner, I had to ask whether it was a compelling enough upgrade for me.  But for someone that is just jumping into mono imaging, the answer may likely be different.  I think you just have to look at them side by side and compare. 

 

Edit:  And the 1600 with 2x2 is 4 megapixels vs. the 174 at 2.3 megapixels.  So its less than twice, but I understand your point. 

Edited by Thirteen, 18 April 2016 - 03:10 PM.

[Thirteen]

 

 

ive been looking for a replacement for the t3i... have been torn between the 174mm and the 1600mm... this post might be the kicker for me. A QE graph would definitely sway me one way or the other

 

According to ZWO, QE is not published by the manufacturer and they claim in-house testing would be difficult.   I'm not sure we will see an absolute QE curver for this chip, unfortunately.   ZWO estimated it to be around 60% for the mono, but there wasn't an explaination on how they arrived at that.

 

Ultimately, I think the decision between the 174 and 1600 should be made on the following considerations:

(1) which is the best fit for image scale (with binning options), then

(2) is the FOV of the 174 too restrictive for your purposes, then

(3) is the supposed QE increase of 15-20% on the 174 important to you. 

 

 

I was out debugging the new computer doing some tests on Jupiter, what hit me was how hard it was to find the thing with such a small chip (using the asi120mm) - it hit me that I might get very frustrated with the 174 if I was struggling to find my target. Your pictures with the 174 are really in the inspiration for me to consider that option, but I'm starting to thing the 1600 might be a better fit for me starting out with mono imaging

 

 

Thanks.   I'd recommend plate solving to find and center your target and then it is less of a concern. 

 

I think it just comes down to the fact that the 1600 is an awesome option for someone starting out from a DSLR.  But, there are some areas where the 174 is a bit better.  FOV is not one of them. 

[matejmihelcic]

My first post I was updated with camera settings.

[calypsob]

The 1600 is the same sensor used in an olympus slr, i forget which one. It is a micro 4/3 sensor, so 35mm lenses will perform very well with this sensor with much less vignette and coma. At 16mp the tiny pixels will gather alot of detail and the smaller sensor with give a tighter field of view, but with 16mp. I would expect the quality to rival and surpass full frame dslrs because setpoint cooling can be utilized. If you are moving past a dslr this might be an interesting option. Its great to see more mono cmos hit the market, wonder if Sam will ever pursue a full frame exmor sensor??

[FiremanDan]

I am really torn between this and a used mono SBIG ST-8300M!!